Gnt MCP server

Run the setup below once and every agent your team runs has a git-native rulebook it has to check over MCP before it acts, approved the same way your code already is: a merged pull request.

• Rules live in your repo as files and ship through normal PRs, not a dashboard click.
• Agents call check_action over MCP before anything risky (a refund, a delete, a message to a customer) and get back an allow/block/escalate verdict.
• Every rule traces back to the git file and the PR that approved it, so "why did the agent do that" always has a paper trail.

Prefer not to run any of this yourself? The hosted version at gntai.dev does the same thing without you standing up a Postgres instance.

Get started (30 seconds)

npm install -g @gnt-ai/cli
gnt login
gnt connect github
gnt prebrain
# merge the opened PR on GitHub. that merge is the approval

Try it with Docker first

To see a real check_action response before installing Node or npm, clone the repository and run the Docker-only demo:

./demo.sh

It builds the full local stack in an isolated gnt-demo Compose project, seeds an approved refund rule, calls checkaction, and prints a curl command you can run again. Without an Anthropic key the real fail-closed path returns needshuman; pass GNTDEMOANTHROPICAPIKEY=sk-ant-... ./demo.sh to opt in to the model's grounded policy verdict. The demo uses deterministic local embeddings and throwaway localhost-only secrets, so it does not need a ZeroEntropy key.

Nothing for gnt prebrain to scan yet? Run gnt init first — it scaffolds rules/ locally

with a couple of example rule files so there's something real to look at and edit, and points

you at gnt prebrain --starter-packs for a curated pack to start from instead.

That merge lands a rule file in your connected repo, shaped like this:

your-repo/
└── rules/
    ├── refund-approval-threshold.md
    └── contract-legal-cc.md

Each file is plain markdown with YAML frontmatter:

---
title: Never refund over $500 without a manager
status: approved
confidence: 0.91
owner_id: finance-team
source_citations: [...]
source: slack
tags: [refunds, finance]
last_validated_at: 2026-07-20
version: 1
superseded_by: null
approved_by: jane@company.com
approved_at: 2026-07-21T14:03:00Z
created_at: 2026-07-18T09:12:00Z
pr_number: 142
pr_url: https://github.com/your-org/your-repo/pull/142
---

Refunds over $500 need manager sign-off before they go out...

See it in action

There's no captured transcript to show yet (see the gap noted at the bottom of this README). Here's the actual response shape a check_action call returns, straight from the tool's contract:

{
  "verdict": "blocked",
  "reason": "Refund exceeds the $500 threshold without manager sign-off (rules/refund-approval-threshold.md)",
  "cited_rules": [
    { "id": "refund-approval-threshold", "title": "Never refund over $500 without a manager" }
  ],
  "rules_retrieved": 3
}

Shortened. The full README is on GitHub.